Connect IK Chains

Blender's Auto IK tool allows us to pose a chain of bones by moving the last bone in the chain. This is reminiscent of inverse kinematics (IK), but involves the bones in the FK chain.

Auto IK is enabled in the Pose Options here. However, Auto IK does not work out of the box with Genesis characters, because 1) all bones in the chain must be connected and 2) it must be possible to move the hand, and those conditions are not met by the Genesis rigs.

If we look closely, we see that the child bones are not connected to their parents, but there is a small offset.

Also, the last bone in the chains (hands and feet), cannot be moved, because the location is locked. The Connect IK Chains tool addresses these problems. The options are:

• Chain Type: Which chains should be connected
  • Arms Only:
  • Legs Only:
  • Arms And Legs: The default.
  • Selected: Use this if you want to connect non-standard chains, such as a dog's tail.
• Location: Where are the bones connected.
  • Child Head: This preserves the child bone's pivot point.
  • Parent Tail: This preserves the orientation of the parent bone.
  • Center: Half-way inbetween.
• Unlock Last Bone: Remove location locks for the last bone in the chain.

And now we can turn on Auto IK and pose Aiko's arm by only moving her hand